Modifiable shrink wrap machine, assembly and related method

ABSTRACT

A machine is disclosed for shrink wrapping a load of a given size. The machine includes a supply conveyor for supplying the load to a wrapping zone, a wrap conveyor disposed in the wrapping zone, the wrap conveyor receiving the load from the supply conveyor, a film supply for supplying a film to the wrapping zone, and a wrap guide disposed in the wrapping zone. The wrap guide guides film received from the film supply in a wrap path proximate the wrap conveyor so as to place the film on the load. The wrap guide includes a removable portion defining a portion of the wrap path. The portion of the wrap path defined by the wrap guide removable portion is sized to correspond to the size of the load. A heat supply shrinks the film so as to shrink wrap the load. Related machines, assemblies and methods are also disclosed.

FIELD OF THE INVENTION

The present invention relates generally to modifiable machines,assemblies, and related methods for shrink wrap packaging loads.Particularly, the present invention relates to machines, assemblies, andrelated methods of guiding film so as to place the film on the loadutilizing a wrap guide having a removable portion sized to correspond tothe size of the load.

BACKGROUND OF THE INVENTION

In conventional shrink wrapping, a load is fed to a wrapping zone inwhich a shrink wrap film is placed on the load. The film is cut intopieces or sheets before or during the placement on the load. The loadand film are then passed into a heating tunnel causing the film toshrink and compress against the load. Typically, the film is cut intosheets large enough to allow for some overlap between edges when placedon the load. During the heating process, the edges may therefore besealed together forming a unitary package.

Some users of shrink wrapping machines use the machines to shrink wraploads having different sizes, such as groups of small or large bottles,or small or large groupings of bottles. In such situations, variousmachine parameters have to be altered when the load size is changed. Forexample, the length of the sheet of film may have to be enlarged toaccommodate a larger load. Also, the path of the portion of the machinethat places the film on the load and/or the speed of wrapping along thepath may have to be changed if the load is of a different size.

Conventional shrink wrap machines have attempted to address issuesraised by shrink wrapping differently sized loads using a number ofapproaches. While these approaches may work in certain situations, theyhave been expensive in terms of complication of parts and assembly ofthe parts, the cost of more highly skilled laborers needed to operatethe machinery, and in terms of repair and replacement of expensive wornparts. For example, conventional shrink wrapping machines have utilizedadjustable wrap guides that alter the wrap path followed for wrapping aload. These guides have been complex to properly adjust and calibrate,and may require removal and replacement of a driven wrap chain. Suchchain replacement can be complex and time consuming. Also, conventionalshrink wrap machines have utilized complex servomotor and/or clutcharrangements to drive wrap guides at the varying speeds used during awrap cycle. These parts are expensive to procure, maintain, and replace.Thus, it would be desirable to achieve simpler solutions than have beencurrently proposed for machines capable of shrink wrapping loads ofdifferent sizes.

Conventional shrink wrapping machines have also utilized servomotorsand/or clutches to drive a cutting knife to cut the film to size forshrink wrapping. The placement of the cutting knife within the machineis fixed. Therefore, since the film speed during a wrap varies, oftendictated by the size of the load, the film speed may or may not be at adesirable speed at the time that cutting is necessary for proper filmsheet sizing. For example, the film may have to be cut at an undesirablyhigh speed for certain load sizes. Cutting at a high speed can produceinaccurate cuts. Alternatively, complex drive systems have been used toslow down or stop the film for cutting when the proper cut locationreaches the fixed knife (see, for example, U.S. Pat. No. 6,128,888).Such systems are also unnecessarily complex and such artificialmanipulation of film speed for cutting causes an uneven flow and induceswear on machine parts.

SUMMARY OF THE INVENTION

According to some aspects of the invention, a machine is disclosed forshrink wrapping a load of a given size. The machine includes a supplyconveyor for supplying the load to a wrapping zone, a wrap conveyordisposed in the wrapping zone, the wrap conveyor receiving the load fromthe supply conveyor, a film supply for supplying a film to the wrappingzone, and a wrap guide disposed in the wrapping zone. The wrap guideguides film received from the film supply in a wrap path proximate thewrap conveyor so as to place the film on the load. The wrap guideincludes a removable portion defining a portion of the wrap path. Theportion of the wrap path defined by the wrap guide removable portion issized to correspond to the size of the load. A heat supply is providedfor shrinking the film so as to shrink wrap the load. Various optionsand modifications are possible.

For example, the wrap guide may include two fixed guide portions and twoof the removable portions, a respective one of each of the fixed guideportions and the removable portions being disposed on each side of thewrap conveyor. The removable portions may define the wrap path having agiven configuration, and the machine may include alternate removableportions that define an alternate wrap path of a differentconfiguration, the alternate removable portions configured for replacingthe removable portions for wrapping an alternate load of a differentsize.

The wrap guide may define a track followed by a follower, the followerbeing pivotally connected to a wrapping bar by a linkage. The wrappingbar may be driven by the follower so as to move the film from the filmsupply into the wrapping zone to place the film on the load. The wrapguide may include a plurality of the followers, wrapping bars andlinkages disposed around the track. The track may be not substantiallycongruent with the wrap path. The removable portions may define the wrappath having a given configuration, and the machine further includingalternate removable portions that define an alternate wrap path of adifferent configuration, the alternate removable portions configured forreplacing the removable portions. The track may be formed by theremovable portions and the alternate removable portions may be notsubstantially congruent. The follower may move around the track atsubstantially constant speed and the wrapping bar moves around the wrappath at a varying speed.

The wrap guide may include a loop driven at constant speed for driving awrapping bar along the wrap path at a varying speed. The wrapping barmay be connected to the loop via a pivoting linkage. The wrapping barmay be driven faster than the wrap conveyor for a portion of the travelof the wrapping bar.

According to other aspects of the invention, a machine is disclosed forselectively shrink wrapping a first load of a first size or a secondload of a second size. The machine includes a supply conveyor forsupplying the first or second load to a wrapping zone, a wrap conveyordisposed in the wrapping zone, the wrap conveyor receiving the first orsecond load from the supply conveyor, a film supply for supplying a filmto the wrapping zone, and a wrap guide disposed in the wrapping zone.The wrap guide guides film received from the film supply in a wrap pathproximate the wrap conveyor so as to place the film on the first orsecond load. The wrap guide includes a removable portion defining aportion of the wrap path and an alternate removable portion defining analternate portion of the wrap path. The portion of the wrap path isdefined by the wrap guide removable portion and the alternate portion ofthe wrap path is defined by the alternate removable portion respectivelybeing sized to correspond to the size of the first or second load. Aheat supply is provided for shrinking the film so as to shrink wrap theload. Again, various options and modifications are possible.

According to other aspects of the invention, a wrapping assembly isdisclosed for a machine for shrink wrapping a load of a given size. Themachine includes a wrap conveyor disposed in the wrapping zone, a filmsupply for supplying a film to the wrapping zone, and a wrap guidedisposed in the wrapping zone. The wrap guide guides film received fromthe film supply in a wrap path proximate the load and the wrap conveyorso as to place the film on the load. The wrap guide includes a removableportion defining a portion of the wrap path. The portion of the wrappath defined by the wrap guide removable portion is sized to correspondto the size of the load. Again, various options and modifications arepossible.

According to certain other aspects of the invention, a method isdisclosed for selectively shrink wrapping a first load of a first sizeand a second load of a second size. The method includes the steps of:(a) installing a removable portion of a wrap guide to define a wrappath, the removable portion defining a portion of the wrap path having afirst configuration; (b) supplying the first load of the first size to awrap conveyor; (c) supplying a film for wrapping the first load; (d)driving the wrap guide in the wrap path proximate the wrap conveyor soas to place the film on the first load; (e) heating the film to shrinkwrap the first load; (f) replacing the removable portion with analternate removable portion defining an alternate portion of the wrappath having a second configuration different from the firstconfiguration; and (g) repeating steps (b) to (e) using the alternateremovable portion and the second load. Various options and modificationsare possible.

For example, the wrap guide may define a track followed by a follower,the follower being pivotally connected to a wrapping bar by a linkage.The wrapping bar may be driven by the follower so as to move the filmfrom the film supply into the wrapping zone to place the film on theload. The wrap guide may include a plurality of the followers, wrappingbars and linkages disposed around the track. The track may be notsubstantially congruent with the wrap path. The follower may move aroundthe track at substantially constant speed and the wrapping bar may movearound the wrap path at a varying speed. The wrap guide may include aloop driven at constant speed for driving a wrapping bar along the wrappath at a varying speed.

According to other aspects of the invention, a method is disclosed forselectively shrink wrapping a load having a size. The method includesthe steps of: (a) selecting a removable portion from a family ofremovable portions dependent on the size of the load, each removableportion having a particular configuration and defining a wrap pathportion having a particular configuration; (b) installing the selectedremovable portion of the wrap guide to define a wrap path; (c) supplyingthe load to a wrap conveyor; (d) supplying a film for wrapping the firstload; (e) driving the wrap guide in the wrap path proximate the wrapconveyor so as to place the film on the load; and (f) heating the filmto shrink wrap the first load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a shrink wrapping machine according tocertain aspects of the invention.

FIG. 2 is a perspective view of a cutting assembly suitable for use inthe device of FIG. 1.

FIG. 3 is a side diagrammatical view of a wrapping assembly suitable foruse in the device of FIG. 1.

FIG. 4A is a side diagrammatical view of the wrapping assembly of FIG. 3showing a first wrapping stage.

FIG. 4B is a side diagrammatical view of the wrapping assembly of FIG. 3showing a second wrapping stage.

FIG. 4C is a side diagrammatical view of the wrapping assembly of FIG. 3showing a third wrapping stage.

FIG. 4D is a side diagrammatical view of the wrapping assembly of FIG. 3showing a fourth wrapping stage.

FIG. 5A is a side diagrammatical view of the wrapping assembly as inFIG. 3, showing one example of a removable portion of a wrap guide ofthe wrapping assembly as in FIG. 3.

FIG. 5B is a side diagrammatical view of the wrapping assembly as inFIG. 3, showing another example of a removable portion of a wrap guideof the wrapping assembly as in FIG. 3.

FIG. 6 is a diagram showing an example of possible film speed during thewrapping cycle and potential film cutting points.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, and notmeant as a limitation of the invention. For example, featuresillustrated or described as part of one embodiment can be used withanother embodiment to yield still a third embodiment. It is intendedthat the present invention include these and other modifications andvariations. In discussing various embodiments, like or similar referencenumerals are used below with like or similar parts of variousembodiments.

FIG. 1 generally shows a shrink wrapping machine 10 useful for shrinkwrapping loads using conventional shrink wrapping films. Machine 10generally includes a supply conveyor 12, a wrap zone 14, in which isdisposed a wrap conveyor 16 and a wrap guide 18, and a heat supply 20. Afilm supply 22 supplies film to a cutting assembly 24, which suppliescut film to the wrapping zone 14. As will become apparent from thefollowing, various aspects, combinations, and sub-combinations offeatures of the above elements are within the scope of the presentinvention. Also, it is possible to bring into practice the inventionsdisclosed below in numerous ways and with numerous modifications.Therefore, the specifics shown in FIG. 1 and the following figuresshould not be considered limiting of the invention, but only as oneexample of how to carry out the various inventive concepts.

FIG. 1 further shows that machine 10 is supported by a frame 30including a number of upright and horizontal members. The various partsof machine 10 may be attached to frame 30 in conventional ways. Forexample, an infeed conveyor 32 may be provided to supply loads to bewrapped to machine 10. Infeed conveyor 32 may be an integral part ofmachine 10, or may be considered part of a separate device or conveyor,depending upon the application. Infeed conveyor 32 may supply grouped,stacked, or boxed loads, or any load to be wrapped, as desired.

Supply conveyor 12 includes a supply belt 34 and a flight bar assembly36 for driving loads received from the infeed conveyor 32 to wrappingzone 14. Supply belt 34 may be driven or undriven, or may be replaced byrollers. Flight bar assembly 36 may include a plurality of flight bars38 driven on chains 40 by a conventional motor drive withservo-clutches. Flight bars 38, supply belt 34 and infeed conveyor 32may all be driven at synchronous speeds as controlled by a programmablelogic controller, as desired. Sensors 42 may be provided within supplyconveyor 12 to detect presence of loads being pushed by flight bars 38for feedback loop control of various aspects of machine 10.

Film supply 22 may include rollers 44 for supporting one or more filmrolls 46 for supplying film to machine 10. Rollers 44 may be driven orundriven. The film F is paid out from film roll 46 through a series ofrollers 48. If desired, rollers 48 may comprise a portion of aconventional dance bar assembly used to provide more steady rotation ofroll 46 while the downstream speed of film F varies due to wrappingcycle film speed changes, as is known.

FIG. 2 shows a perspective view of cutting assembly 24 according tocertain aspects of the present invention. As shown, film F enters alower portion of cutting assembly 24 threading around a first roller 52,a second roller 54, between pinch rollers 56 and past exit roller 58.Cutting assembly 24 includes a frame 60 including a base 62 and sidepieces 64. Mounting plates 66 are attached to side pieces 64. Roller 52is an idler roller mounted between side pieces 64. Rollers 54 and 58 areidler rollers mounted between mounting plates 66. At least one of pinchrollers 56 mounted between mounting plates 66 is driven. It should beunderstood that various different arrangements of rollers or otherstructures for passing film F from film supply 22 to and through cuttingassembly 24 could be utilized, if desired.

A vacuum belt 68 is mounted between side pieces 64. Vacuum belt 68 maybe a conventional vacuum belt used for transmitting film in a desireddirection, as is known. Vacuum belt 68 may be driven with a variablespeed so as to move cut film at a desired wrapping speed. Thus, vacuumbelt 68 may be driven via a variable speed servomotor, a controlled by aconventional programmable logic device. Film speeds during differentportions of a wrapping cycle will be discussed in further detail below.

Cutting assembly 24 further includes a cutting mechanism 70 mountedwithin frame 60. As shown, cutting mechanism 70 may include a cuttingblade 72 rotationally mounted within mounting plates 66. Cuttingmechanism 70 may be driven by the same servomotor used to drive vacuumbelt 68, and is triggered by an electronic clutch 74. It can bedesirable to cause cutting blades 72 to be rotated by the servomotor andelectronic clutch 74 so as to be substantially synchronized intangential speed with the speed of film F. It is believed that suchsynchronization of the cutting mechanism and the film speeds creates amore accurate cut.

In some aspects of the present invention, it is desirable to selectivelyfix the position of the cutting mechanism within a cutting zone withincutting assembly 24. As shown in FIG. 2, rack gears 76 may be providedalong side pieces 64 to mesh with pinion gears 78 attached to mountingplates 66. The rotation of handle 80 causes pinion gears 78 to rotaterelative to rack gears 76, thereby positioning cutting mechanism 70 at apredetermined location along the cutting zone within cutting assembly24. Guides 82 assist in maintaining alignment along rack gear 76. Thus,rack gears 76 may be said to comprise a track along a cutting zone, withcutting mechanism 70 being positionable along the track. If desired, asensor 84 may be utilized to determine position along the track, such asby using an optical sensor to count teeth of rack gears 76, etc., orsome equivalent.

As will be discussed in further detail below, use of handle 80 toposition cutting mechanism 70 within the cutting zone between rack gears76 can provide certain benefits in certain applications. For example,cutting mechanism 70 may be placed in a position so as to achieve acertain length of cut film, or so as to cut the film at a certain pointin the wrap cycle, or at a certain film speed, or within a range of filmspeeds. However, it should be understood that the movable cuttingmechanism 70 is not required for all aspects of the invention.

It should also be understood that other cutting mechanism locationadjustment designs could be substituted for the rack and pinionarrangement shown in FIG. 2. Thus, a hydraulic, pneumatic, or electricadjustment assembly could be used. Also, other continuously orselectively (step-wise) adjustable mechanisms could be utilized, ifdesired. Although the cutting mechanism 70 of FIG. 2 as shown isconfigured to be positioned while machine 10 is not running (i.e. isonly to be positioned while the machine is stopped), it would also bepossible to configure cutting assembly 24 so that the location ofcutting mechanism 70 would be repositionable during use of machine 10,if desired. Thus, various options and modifications are possible for theelements of cutting assembly 24 shown in FIG. 2.

FIG. 3 shows a diagram of one example of equipment useful in a wrap zone14 according to certain aspects of the invention. More specifically,FIG. 3 shows a side view of one side of wrap guide 16 that would bedisposed adjacent wrap conveyor 18 (see FIG. 1). Wrap guide 16 isdisposed in wrapping zone 14 for guiding film received from film supply22 via cutting assembly 24 in a wrap path. Wrap guide 16 includes afixed portion 100 and a removable portion 102. Fixed portion 100 isfixed to frame 30, and removable portion 102 is fixed to frame 30 andthe fixed portion. Together, the fixed and removable portions 100 and102 define a wrap path 108 for film being wrapped around a given load.

Wrap guide 16 further includes at least one wrapping bar 104 drivenalong the wrap path. Wrapping bar 104 is mounted to a follower 106 thatfollows a chain 116 along a track 117. Fixed portion 110 of wrap path108 is disposed within fixed portion 100 of wrap guide 16. Removableportion 112 of wrap path 108 is disposed within removable portion 102 ofwrap guide 16. Linkages 114 are connected to followers 106, and are inturn driven by chain 116. Driven gear 118 drives chain 116, and gear 120is an idler gear. Machine main drive assembly 122 is schematically shownas connected to driven gear 118 by belt 124.

If desired, main drive assembly 122 may be utilized to drive chain 116at a substantially constant speed. The track 117 followed by chain 116is fixed. However, wrap path 108 may have differing shapes, dependingupon the size of the load, the length of the linkages 114, etc. Thus, bydesigning track portion 112 accordingly, different sized loads may bewrapped without modifying main drive assembly 122 or chain 116 or itspath. The profile along portion 112 of track 108 defines the path thatwrap bars 104 take along the wrap path when wrapping a load with film.Quick-connect assembly devices such as clamps 126 may be utilized toreadily attach and detach removable portion 102 so as to change thetrack portion 112 if desired. Thus, if different sized loads are to bewrapped using machine 10, a simple change out of portions 102 on eitherside of wrap guide 116 can accommodate the different sized loads byproviding a different wrap path. By designing track portion 112 andlinkage length 114 accordingly, varying wrap paths can be achieved. Insuch situation, chain 116 may continue to be driven at a substantiallyconstant speed using main drive 122. Further, the orientation and/orlocation of chain 116 within machine 10 need not be changed, or theactual chain itself need not be changed out for different loads. Thus,it is a relatively simple matter to change the size and/or shape of loadbeing wrapped by machine 10 by simply changing out the removableportions 102 of a first predetermined size for a second alternateremovable portions of another predetermined size to provide alternatewrap paths of different configurations. However, the track 117 followedby chain 116 does not change when removable portions 102 are changed.

FIGS. 4A-4D show a portion of a wrap cycle in which cut film F istransferred from vacuum belt 68 to load L for wrapping the load. Asshown therein, film F is fed so as to provide a leading edge that iscaptured beneath load L (between FIGS. 4B and 4C). As load L movesfurther to the left between FIGS. 4B and 4C the wrap bar 104 attached tolinkage 114 a is driven into contact with the cut film and is pulledover and around load L as it moves through wrap zone 14 along wrapconveyor 18. As shown in FIG. 4D, cut film F has been looped over top ofload L. As load L moves further to the left from the position shown in4D, the trailing edge of cut film will overlap with the leading edgebeneath load L. At that point, the load will be ready for passing into aheat supply, such as a tunnel or oven 20, as shown in FIG. 1. Chain 116may be driven at a substantially constant speed during this wrap cycle.

The wrap path 108 generated by fixed and removable portions 100 and 102,in combination with linkage 114 causes the cut film to acceleratesubstantially between the positions of FIGS. 4C and 4D so that the cutfilm will essentially pass over and in front of the load. Film speedswill be discussed below in connection with FIG. 6.

FIGS. 5A and 5B show two alternate constructions whereby different sizedwrap paths are created by providing different sized removable portions102. In FIG. 5A, linkage 114 is replaced by linkage 114 a as well asreplacing removable portion 102 with removable portion 102 a. Wrap pathportion 112 a in removable portion 102 a is defined accordingly. In FIG.5B, linkage 114 is not replaced when removable portion 102 is replacedby removable portion 102 b. Accordingly a different alternate wrap pathportion 112 b is created. FIGS. 5A and 5B illustrate that, through arelatively simple change out of removable portions 102, with an optionalchange out of linkages 114, alternate wrap paths may be readilyachieved, thereby allowing differently sized loads to be wrapped usingthe same equipment with minimal changes. Such change out can be donereadily during operation requiring less down time and less technicallyskilled labor personnel to achieve such change out, than if the drivechain had to be changed out or its path modified.

Also, driving a wrap assembly by driving wrap bars through such alinkage attached to a substantially constant speed loop, such as chain116, allows for a relatively simple mechanism for providing a wrap pathhaving a wrap bar that moves at a substantially varying speed.Therefore, instead of complex servomotors and controls, a simpler andless expensive drive may be used along with a linkage and wrap pathspaced from a chain track, to achieve a desired changing film speedduring load wrapping.

One example of such a film speed distribution is shown in FIG. 6. Moreparticularly, FIG. 6 shows one wrap cycle divided into 360 degreesaccording to the position of a wrap bar 104 on chain 116. In FIG. 6, the0 degrees position is with the wrap bar 104 at a “3 o'clock” positionaround track 117, as shown in FIG. 3. As shown in FIG. 6, the speed ofwrap bar 114 increases from 90 to 170 degrees. Such point corresponds toposition shown, for example, in FIG. 4C where wrap bar is advancing filmF from behind and over the load to be wrapped. Essentially, the wrap barmust speed up to a speed faster than the synchro speed of the load andpast the load so that the leading and trailing edges may overlap. At 190to 270 degrees the speed of wrap bar 104 slows down as the wrap barreturns for another cycle.

It should be understood that the speed profile as shown in FIG. 6 canvary a great deal according to the present invention. For example, thespeed increases and decreases need not be linear, the speeds need notreach constant levels, etc. The speeds are essentially a function of thesize of the guide path and the length of the linkages, as well as thespeed of the load through the wrap zone. In any event, the wrap bar 104will typically have to accelerate as it picks up a piece of cut filmfrom behind the load, passes over top of the load, and then passes downin front of the load so as to allow for overlapping of the cut film.Thus, there is a base speed and an acceleration portion found in thecurve. Again, it should be kept in mind that multiple wrap bars may beused, so the curve could show a similar speed profile in 0 to 180degrees, 0 to 120 degrees, 0 to 90 degrees of chain rotation, dependingon the number of wrap bars attached to the chain.

If desired, it can be useful in certain applications to selectively cutthe film at particular points along the speed curve. For example, it maybe desired to cut the film when it is moving at a speed less than themaximum speed. It may also be useful to cut the film at a minimum speed,or somewhat proximate the minimum speed. In such case a less expensivelow speed clutch may be used and synchronizing blade speed and filmspeed is less complicated. Thus, if desired, the position of cuttingmechanism 70 within the cutting zone may be altered by using the rackand pinion gears 76 and 78 so as to locate the cutting mechanism so asto achieve cutting at a desired film speed for the desired application.Accordingly, one may therefore choose a position of cutting mechanism 70depending upon one or more of a size of the load, a length of the filmafter cutting (so as to wrap the film about the load), a point in thewrap cycle in which the cutting mechanism is to cut the film, an amountof leading edge of the film to be placed beneath the load during thewrap cycle, etc. Therefore, having a cutting mechanism with anadjustable positioning device can provide certain benefits.

It is believed that programming can be created to assist in setting theoptimal position of the cutting mechanism within the cutting zone basedon various system parameters, such as load size, wrap path dimensions,machine speed, etc. Such optimum position could also be determinedempirically through testing and experience. In any event, the optimalplacement may be provided to a machine user for manual manipulation ormay be automatically achieved by a drive mechanism, for example throughthe use of programmable logic servomotors, position sensors, etc. Ifdesired, such positioning could be automatically achieved duringoperation as well based on various sensor input.

According to certain other aspects of the invention, methods of usingthe above shrink wrap machine components are also contemplated withinthe scope of the invention. For example, it is within the scope of theinvention to wrap a load of a certain size using a first removableportion of a wrap guide, switching out that removable portion for analternate removable portion of a different size defining a differentwrap path, and then wrapping a load of a different size. Similarly, onemay fix the cutting mechanism at a certain position, run the machine towrap a load of a given size, and then move cutting mechanism to adifferent position so as to cut film so as to wrap loads of a differentsize. The methods may be complementary or may be employed separately, ifdesired. Thus, the machine and methods described above provide aflexible wrapping machine that can be utilized for different loads andfor different applications, where change out and down time, if loads ofdifferent sizes are to be wrapped, is reduced.

It should be understood that various other modifications andcombinations of the above embodiments are contemplated and are alsowithin the scope of the present invention. Thus, the present inventioncontemplates that any and all such subject matter is included within thescope of the present invention.

1. A machine for shrink wrapping a load of a given size, the machinecomprising: a supply conveyor for supplying the load to a wrapping zone;a wrap conveyor disposed in the wrapping zone, the wrap conveyorreceiving the load from the supply conveyor; a film supply for supplyinga film to the wrapping zone; a wrap guide disposed in the wrapping zonefor guiding film received from the film supply in a wrap path proximatethe wrap conveyor so as to place the film on the load, the wrap guideincluding a removable portion defining a portion of the wrap path, theportion of the wrap path defined by the wrap guide removable portionbeing sized to correspond to the size of the load; and a heat supply forshrinking the film so as to shrink wrap the load.
 2. The machine ofclaim 1, wherein the wrap guide includes two fixed guide portions andtwo of the removable portions, a respective one of each of the fixedguide portions and the removable portions being disposed on each side ofthe wrap conveyor.
 3. The machine of claim 1, wherein the removableportions define the wrap path having a given configuration, and furtherincluding alternate removable portions that define an alternate wrappath of a different configuration, the alternate removable portionsconfigured for replacing the removable portions for wrapping analternate load of a different size.
 4. The machine of claim 1, whereinthe wrap guide defines a track followed by a follower, the followerbeing pivotally connected to a wrapping bar by a linkage.
 5. The machineof claim 4, wherein the wrapping bar is driven by the follower so as tomove the film from the film supply into the wrapping zone to place thefilm on the load.
 6. The machine of claim 4, wherein the wrap guideincludes a plurality of the followers, wrapping bars and linkagesdisposed around the track.
 7. The machine of claim 4, wherein the trackis not substantially congruent with the wrap path.
 8. The machine ofclaim 4, wherein the removable portions define the wrap path having agiven configuration, and further including alternate removable portionsthat define an alternate wrap path of a different configuration, thealternate removable portions configured for replacing the removableportions.
 9. The machine of claim 8, wherein the track formed by theremovable portions and the alternate removable portions are notsubstantially congruent.
 10. The machine of claim 4, wherein thefollower moves around the track at substantially constant speed and thewrapping bar moves around the wrap path at a varying speed.
 11. Themachine of claim 1, wherein the wrap guide includes a loop driven atconstant speed for driving a wrapping bar along the wrap path at avarying speed.
 12. The machine of claim 11, wherein the wrapping bar isconnected to the loop via a pivoting linkage.
 13. The machine of claim11, wherein the wrapping bar is driven faster than the wrap conveyor fora portion of the travel of the wrapping bar.
 14. A machine forselectively shrink wrapping a first load of a first size or a secondload of a second size, the machine comprising: a supply conveyor forsupplying the first or second load to a wrapping zone; a wrap conveyordisposed in the wrapping zone, the wrap conveyor receiving the first orsecond load from the supply conveyor; a film supply for supplying a filmto the wrapping zone; a wrap guide disposed in the wrapping zone forguiding film received from the film supply in a wrap path proximate thewrap conveyor so as to place the film on the first or second load, thewrap guide including a removable portion defining a portion of the wrappath and an alternate removable portion defining an alternate portion ofthe wrap path, the portion of the wrap path defined by the wrap guideremovable portion and the alternate portion of the wrap path defined bythe alternate removable portion respectively being sized to correspondto the size of the first or second load; and a heat supply for shrinkingthe film so as to shrink wrap the load.
 15. The machine of claim 14,wherein the wrap guide defines a track followed by a follower, thefollower being pivotally connected to a wrapping bar by a linkage. 16.The machine of claim 15, wherein the wrapping bar is driven by thefollower so as to move the film from the film supply into the wrappingzone to place the film on the load.
 17. The machine of claim 15, whereinthe wrap guide includes a plurality of the followers, wrapping bars andlinkages disposed around the track.
 18. The machine of claim 15, whereinthe track is not substantially congruent with the wrap path.
 19. Themachine of claim 15, wherein the follower moves around the track atsubstantially constant speed and the wrapping bar moves around the wrappath at a varying speed.
 20. The machine of claim 15, wherein the wrapguide includes a loop driven at constant speed for driving a wrappingbar along the wrap path at a varying speed.
 21. A wrapping assembly fora machine for shrink wrapping a load of a given size, the machinecomprising: a wrap conveyor disposed in the wrapping zone; a film supplyfor supplying a film to the wrapping zone; and a wrap guide disposed inthe wrapping zone for guiding film received from the film supply in awrap path proximate the load and the wrap conveyor so as to place thefilm on the load, the wrap guide including a removable portion defininga portion of the wrap path, the portion of the wrap path defined by thewrap guide removable portion being sized to correspond to the size ofthe load.
 22. The assembly of claim 21, wherein the wrap guide includestwo fixed guide portions and two of the removable portions, a respectiveone of each of the fixed guide portions and the removable portions beingdisposed on each side of the wrap conveyor.
 23. The assembly of claim21, wherein the removable portions define the wrap path having a givenconfiguration, and further including alternate removable portions thatdefine an alternate wrap path of a different configuration, thealternate removable portions configured for replacing the removableportions for wrapping an alternate load of a different size.
 24. Theassembly of claim 21, wherein the wrap guide defines a track followed bya follower, the follower being pivotally connected to a wrapping bar bya linkage.
 25. The assembly of claim 24, wherein the track is notsubstantially congruent with the wrap path.
 26. The assembly of claim24, wherein the removable portions define the wrap path having a givenconfiguration, and further including alternate removable portions thatdefine an alternate wrap path of a different configuration, thealternate removable portions configured for replacing the removableportions.
 27. The assembly of claim 24, wherein the follower movesaround the track at substantially constant speed and the wrapping barmoves around the track at a varying speed.
 28. The assembly of claim 24,wherein the wrap guide includes a loop driven at constant speed fordriving a wrapping bar along the wrap path at a varying speed.
 29. Theassembly of claim 21, further including a supply conveyor for supplyingthe load to the wrap conveyor.
 30. The assembly of claim 21, furtherincluding a heat supply for shrinking the film so as to shrink wrap theload.
 31. A method for selectively shrink wrapping a first load of afirst size and a second load of a second size, the method comprising thesteps of: (a) installing a removable portion of a wrap guide to define awrap path, the removable portion defining a portion of the wrap pathhaving a first configuration; (b) supplying the first load of the firstsize to a wrap conveyor; (c) supplying a film for wrapping the firstload; (d) driving the wrap guide in the wrap path proximate the wrapconveyor so as to place the film on the first load; (e) heating the filmto shrink wrap the first load; (f) replacing the removable portion withan alternate removable portion defining an alternate portion of the wrappath having a second configuration different from the firstconfiguration; and (g) repeating steps (b) to (e) using the alternateremovable portion and the second load.
 32. The method of claim 31,wherein the wherein the wrap guide defines a track followed by afollower, the follower being pivotally connected to a wrapping bar by alinkage.
 33. The method of claim 32, wherein the wrapping bar is drivenby the follower so as to move the film from the film supply into thewrapping zone to place the film on the load.
 34. The method of claim 32,wherein the wrap guide includes a plurality of the followers, wrappingbars and linkages disposed around the track.
 35. The method of claim 32,wherein the track is not substantially congruent with the wrap path. 36.The method of claim 32, wherein the follower moves around the track atsubstantially constant speed and the wrapping bar moves around the wrappath at a varying speed.
 37. The method of claim 31, wherein the wrapguide includes a loop driven at constant speed for driving a wrappingbar along the wrap path at a varying speed.
 38. A method for selectivelyshrink wrapping a load having a size, the method comprising the stepsof: (a) selecting a removable portion of a wrap guide from a family ofremovable portions dependent on the size of the load, each removableportion having a particular configuration and defining a wrap pathportion having a particular configuration; (b) installing the selectedremovable portion of the wrap guide to define a wrap path; (c) supplyingthe load to a wrap conveyor; (d) supplying a film for wrapping the load;(e) driving the wrap guide in the wrap path proximate the wrap conveyorso as to place the film on the load; and (f) heating the film to shrinkwrap the first load.